A liquid crystal display (LCD) device is one example of display devices that are used as high-definition color monitors for computers and other information devices, and as television receivers. An LCD device fundamentally includes a display portion in which liquid crystals are sandwiched between two substrates. The two substrates are arranged to face each other in an opposed manner with liquid crystal sandwiched therebetween. The two substrates include a Thin Film Transistor (TFT) substrate and a counter substrate or a color filter substrate which is arranged to face the TFT substrate in an opposed manner with the liquid crystal sandwiched therebetween. The TFT substrate comprises several elements including TFTs, pixel electrodes, gate lines and data lines. The gate lines are arranged parallel to each other and data lines are arranged perpendicular to the gate lines. Each data line is electrically connected with one end of a semiconductor layer. A connection portion of the data line which is connected with the semiconductor layer functions as a drain electrode of the TFT.
The counter substrate which is arranged to face the TFT substrate with the liquid crystal sandwiched therebetween also comprises several elements. The counter substrate includes light blocking films or black matrices (BMs). The black matrices are formed so as to overlap the data lines which are formed on the TFT substrate. The black matrices are arranged parallel to each other. Further, color sub pixels or color filters are provided in such a manner that each color filter is formed between the neighboring black matrices. These color filters can be arranged in order of a green color filter (G), a red color filter (R), a blue color filter (B), a green color filter (G), a red color filter (R), . . . , for example. Regions which are covered with the red color filters (R) constitute red sub pixels, regions which are covered with the blue color filters (B) constitute blue sub pixels, and regions which are covered with the green color filters (G) constitute green sub pixels, and these sub pixels are arranged adjacent to each other. These three sub pixels having different colors constitute a unit pixel for the color display.
In the LCD device having the above-mentioned constitution, when the display screen is viewed from an oblique angle, there arises a problem referred to as color mixing. Color mixing occurs when a color of a sub pixel in the OFF state which is arranged adjacent to a sub pixel in the ON state, appears to be mixed with color of the sub pixel in the ON state. This issue usually arises for sub pixels located close to a side edge of the display screen and are viewed from an oblique angle close to the opposite side edge of the display. This is because a light from a backlight may pass through the sub pixel in the OFF state and reach the viewer who is looking at the display from an opposite corner on an oblique angle.